用于侧向接发停车货物列车并位于正线的单开道岔，在中间站道岔辙叉号数不得小于（）。
A、9号
B、12号
C、18号
D、30号
参考答案：B
根据地外行星与太阳的黄经差从0°、90°、180°到270°，相应的行星位置为（）。
Which of the following statements regarding a sinking fund provision is TRUE A sinking fund provision:（）
A. requires that the issuer should set aside money based on a predefined schedule to accumulate the cash to retire the bonds at maturity.
B. requires that the issuer should retire a portion of the principal through a series of predefined principal payments over the life of the bond.
C. must be made through the payment of cash, paid to the trustee based on a predetermined schedule.
